This invention is an improvement on cement lasting machines of the type shown in U.S. Pat. No. 3,963,840.
Dealing with a first aspect of the invention, the prior art machine is operable on a shoe assembly formed of a last having an insole located on its bottom and an upper mounted thereon with the toe portion of the upper margin being wiped against and secured to the insole and unwiped portions of the upper margin extending heelwardly of the wiped toe portion of the upper margin. The machine applies cement in the corners between the unwiped margin portions and the corresponding portions of the insole periphery. The machine includes a shoe assembly support for supporting the shoe assembly bottom-up with the toe end of the shoe assembly facing forwardly. A pair of nozzles, located above the shoe assembly, are mounted for forward-rearward movement, for heightwise movement, and for inward-outward movement. In order to apply cement into the corners heelwardly from the boundaries between the wiped and unwiped margin portions, the nozzles are caused to move forwardly while they are in upper and inner positions until an engaging member, that is mounted for forward-rearward movement with the nozzles, intersects a stop member. The stop member is so located as to stop the forward movement of the nozzles when the nozzles are over the widest part of the shoe assembly bottom heelwardly of said boundaries. After the stop member stops forward movement of the nozzles, the nozzles are lowered and moved outwardly into the corners heelwardly of said boundaries. The stop member is then moved out of intersecting relationship with the engaging member so that the nozzles can again resume their forward movement so as to bring the nozzles to said boundaries. When the nozzles have arrived at said boundaries, they are caused to move rearwardly while being maintained in said corners and cement is extruded from the nozzles into the corners during this rearward movement. In order to properly stop the first mentioned forward movement of the nozzles in the appropriate position for the particular length of shoe being operated on, the forward-heelward location of the stop member is manually adjusted.
A first object of the first aspect of the invention is to do away with the manual adjustment of the forward-rearward location of the stop member when changing the length of the shoe assembly being operated on by the machine. To accomplish this, the machine, in accordance with the first aspect of the invention, includes a detector member mounted for forward-rearward movement that is so connected to the stop member as to cause the stop member to have forward-rearward movement in unison with the detector member. The detector member is initially located in a forward position that is toeward of the toe and extremity of the shoe assembly and is yieldably moved rearwardly, together with the stop member, prior to the first mentioned forward movement of the nozzles to bring the detector member into engagement with the toe and extremity of the shoe assembly and thereby bring the stop member to the desired location for the particular length of shoe assembly being operated on.
A second object of the first aspect of the invention is to provide an improved arrangement for moving the stop member out of intersecting relationship with the engaging member after the engaging member has intersected the stop member to stop the first mentioned forward movement of the nozzles and for stopping the resumed forward movement of the nozzles when the nozzles have arrived at said boundaries. This is accomplished by mounting the stop member to a housing for forward movement from a rearward stop member position which is the position the stop member assumes when the engaging member engages the stop member to stop the first mentioned forward movement of the nozzles and a forward stop member position that is in intersecting relationship with the engaging member. After the stop member, in its rearward stop member position, has been engaged by the engaging member to stop the forward movement of the nozzles and the nozzles have been moved into said corners, the stop member is moved to its forward stop member position to permit resumption of the forward movement of the nozzles until the engaging member again intersects the stop member, the parts being so related that the second intersection of the engaging member with the stop member takes place when the nozzles have arrived at said boundaries.
Dealing with a second aspect of the invention, in the operation of the prior art machine, the unwiped portions of the upper margin are the side and heel portions. The prior art machine includes a slide plate, located rearwardly of the support, mounted for forward-rearward movement. Heel wiping means are mounted to the slide plate for forward movement with respect to the slide plate in a heel wiping stroke from a retracted position wherein the heel wiping means is in a position in readiness for wiping to an advanced position wherein the heel wiping means has wiped the heel portion of the upper margin against the corresponding portion of the insole periphery. A shoe assembly engaging member is mounted to the slide plate below the heel wiping means. A side wiping means is located on each side of the support, each side wiping means being mounted for inward movement from a position of disengagement with the shoe assembly through a side wiping stroke to an inner position wherein the side wiping means has wiped a side portion of the upper margin against a corresponding portion of the insole periphery. The slide plate is initially maintained in its rearward position, the heel wiping means is initially maintained in its retracted position, and the side wiping means are initially maintained in their positions of disengagement. Thereafter, the slide plate is moved forwardly until the shoe assembly engaging member engages the heel and extremity of the shoe assembly. This is followed by the imparting of inward movements of each side wiping means from its position of disengagement through a side wiping stroke and outward movement of each side wiping means back to its position of disengagement. After the side wiping means have returned to their positions of disengagement, a heel wiping stroke is imparted to the heel wiping means.
In the prior art machine, the wiping strokes are imparted sequentially to the side and heel wiping means because there is some overlap in the upper margin portions engaged by the side wiping means and the heel wiping means and it is necessary to have the side wiping means returned to their positions of disengagement prior to the imparting of the heel wiping stroke to prevent undesired interference between the side wiping means and the heel wiping means during the side wiping strokes and the heel wiping stroke. It is, however, desirable to have the side and heel wiping strokes take place simultaneously in order to minimize the time of the operating cycle of the machine in operating on a shoe assembly.
In accordance with the second aspect of this invention, the prior art machine has been modified so as to enable the side wiping strokes and the heel wiping stroke to automatically take place simultaneously regardless of the length of the shoe assembly and the position of engagement of the shoe assembly engaging member with the heel end extremity of the shoe assembly. This is accomplished by mounting each side wiping means for forward-rearward movement and by so connecting each side wiping means to the slide plate as to cause forward movement of both side wiping means concomitantly with the forward movement of the slide plate.
Dealing with a third aspect of the invention, each nozzle of the prior art machine is mounted for movement from a starting position to a final position along the workpiece formed by the shoe assembly. A motor, connected to the nozzle, is operable to effect the nozzle movement. The motor is initially caused to maintain the nozzle stationary in its starting position and is then operated to effect said nozzle movement. Extruding means effect extrusion of cement from the nozzle during the nozzle movement to apply cement along a surface of the workpiece.
It is desirable that the extruding means apply a substantially uniform quantity of cement along the surface of the workpiece during the nozzle movement. However, in the prior art machine the motor moves the nozzle from its starting position up to a desired speed along the workpiece so that the nozzle travels slower than this desired speed at the beginning of the nozzle movement, and, in the prior art machine the cement is extruded from the nozzle at a constant rate during the nozzle movement. Therefore, the quantity of cement applied by the nozzle to the workpiece at the beginning of the nozzle movement is greater than the quantity of cement applied by the nozzle to the workpiece during the remainder of the nozzle movement. It is the object of the third aspect of the invention to overcome this deficiency and enable the nozzle to apply a substantially uniform quantity of cement along the surface of the workpiece during the entire movement of the nozzle along the surface of the workpiece. In order to accomplish this object, the prior art machine has been improved by providing first extrusion rate control means, effective at the beginning of the nozzle movement when the motor is moving the nozzle at a relatively slow speed, to cause the extruding means to extrude the cement from the nozzle at a realtively slow rate and by providing second extrusion rate control means, operable after the nozzle has moved a prescribed distance from its starting position that is less than the distance from its starting position to its final position at which time the motor is moving the nozzle at a relatively high speed, to cause the extruding means to extrude the cement from the nozzle at a relatively high rate.